New technologies, especially electronic, biological, and social technologies, are changing the nature and scope of police work. Enchanced police capabilities may result in misuses that will require a reexamination of the scope of limitations on police powers. Electronic surveillance technologies have repeatedly challenged the scope of protection against reasonable searches because they have repeatedly modified the 'reasonable expectation of privacy.' Both remote and intimate sensing technolgies, as well as aggregation of information in computer data bases, similarly expand Government powers and may become more pervasive and invasive in the future. New weaponry may raise issues about the unnecessary use of force. Social science research, predictive models, simulations, and expert systems, increasingly used in criminal justice decisionmaking (e.g., sentencing, probation, parole), have the potential for being discriminatory. Pressure for increased apprehension and punishment of offenders have contributed to prison overcrowding. This, in turn, has led to the use of electronic monitoring of releases and drug and hormone treatment of violent and antisocial offenders that may be challenged on privacy, due process, equal protection, nondiscrimination, or cruel and unusual punishment grounds. Advances in criminal justice recordkeeping raise issues of data quality and confidentiality. While many technological advances offer significant social benefits, they may be a double-edged sword. Diligent attention is required to prevent abuses. Chapter footnotes.